RE: [Xen-devel] FLR support in xl tool stack

[Ross Philipson <Ross.Philipson@xxxxxxxxxx>]

Yeah when I first implemented this in pciback is was looking for a common place 
since the existing FLR logic was in the xend tool-stack (which we were not 
using). Also folks on xen-devel had suggested it go in pciback at the time.

I am not familiar with what reset functionality is in pci in newer kernels 
(there was not a lot in the .27 one) but a lot of what I put in pciback was 
specific to resetting the Intel graphics device on GM45 and Q45 chipsets.

Thanks
Ross

-----Original Message-----
From: Jean Guyader [mailto:jean.guyader@xxxxxxxxx] 
Sent: Thursday, January 27, 2011 11:20 PM
To: Kay, Allen M
Cc: xen-devel; Wilk; Stefano Stabellini; Jean Guyader; Ian Campbell; Thomas 
Horsten; Ross Philipson
Subject: Re: [Xen-devel] FLR support in xl tool stack

On 28 January 2011 08:38, Kay, Allen M <allen.m.kay@xxxxxxxxx> wrote:
> In xm tool stack, there is a function called do_FLR() located in 
> python/xen/util/pci.py that takes care of issuing FLR to passthrough PCI 
> devices.  This function is responsible for looking at the device and figure 
> out the most appropriate way to reset the device (PCI/PCIe FLR, secondary bus 
> reset, etc...).
>
> In xl tool stack, I see there is a libxl_device_pci_reset() in 
> libxl/libxl_pci.c that suppose to do the similar thing.  It references 
> /sys/bus/pci/drivers/pciback/do_flr and tries to write something to it. 
>  However, pciback driver in 2.6.32.27 pvops kernel does not seem to have this 
> do_flr functionality.
>
> Is this something being worked on but not checked in to pvops dom0 kernel yet?
>
> If not, I would prefer implementing all of the do_FLR() functionaility in 
> libxl and not to depend on pciback driver given it is not part of the 
> upstream kernel.  This will make using newer kernels such as 2.6.38 much 
> easier.
>
> Comments?
>

On the newest kernels (I don't know from which version), the reset function has 
been moved under the pci device tree directly. So 
/sys/bus/pci/device/<BDF>/reset.

Jean

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